As a continuation and expansion of previous work, the primary objective of the project is to contribute to the body of scientific information concerning the comparative anatomy (morphology, histology, cytology) and evoluton of the vertebrate labyrinth. Studies will utilize techniques of light microscopy, SEM and TEM. Specific investigations will include: 1) a survey of the occurrence of gap junctions in labyrinthine neuroepithelia in a selected series of reptiles; 2) an investigation of possible membrane recycling and synaptic vesicle formation at afferent synaptic sites in labyrintinine neuroepithelia in Anolis; and 3) a developmental study of the basilar papilla in the Peking duck.